Current invention corresponds to a mobility vehicle that draws its properties from a special kind of a track that can change its rigidity. The track can become rigid on its lower part corresponding to a wheel shape with large diameter or become totally flexible as usual track on upper side for practical use. When rigid, the track correspond to circular wheel and thus plays a role of a wheel in contact with the ground. The upper part of the track remains flexible and allows to use space above a the track for practical reasons. More particularly, the invention relates to a mobile system including variable flexibility track and at least two rollers around which the variable flexibility track is wrapped, wherein the rollers are adapted to change the rigidity and the curvature of the track to adapt its shape to different functionalities as being a wheel or having a part of circular wheel with different curvature or being foldable. The variable flexibility track is composed of track elements and hinges linking the track elements so as to allow rotation of the track elements with respect to each other around the hinges. Each track element bears a locking mechanism that allows a rigid positioning of the track elements with respect to the adjacent ones at various angles. The rollers are in contact with the variable flexibility track and can contain mechanisms to lock a track elements thus changing track rigidity and/or mechanisms to change track curvature. The tracks also play a role of shock absorbers and bear mechanisms to perform turning of the vehicle by applying different speed and/or curvature to the tracks.